Medical monitors are used in a variety of clinical applications, e.g., in the operating room, in the anesthesia or recovery room, in the intensive care unit or in the delivery room. They are, for example, used to monitor the electrocardiogram, respiration, body temperature, various blood gases, and so on, of a patient in order to carry out a clinically meaningful evaluation of the patient's condition. Monitors of this type usually comprise a box or casing containing the printed circuit boards with the electronic circuitry necessary to process, filter, etc., the physiological signals received from a sensor or transducer connected with the medical monitor. The output is then either displayed in numerical form or as a wave, e.g., on a cathode ray tube (CRT) or a 7-segment display. In addition, or as an alternative, the output may also be recorded on a printer and/or fed to a central station or the like.
For the purpose of interconnection with a central station, other monitors, recorders, etc., most medical monitors are additionally equipped with jacks located at the rear panel of the casing. Examples of such connectors are:
a) a digital system connector, i.e., a connector for exchanging digital data indicative of patient waves, trends, alarm messages, etc., with a central station; PA1 b) a digital or analog output for feeding signals, waves, etc., to another monitor for display, or to a recorder; PA1 c) digital or analog inputs, e.g., for receiving signals from another device, for the purpose of displaying, printing or recording; PA1 d) an output for feeding digital or analog signals to a slave display or via communication lines--such as a telephone link--to a remote place, e.g., the physician's home.
The above list contains only some examples of situations where a connection of a medical monitor with another device is necessary. Other kinds of connections may be required as well.
A specific embodiment of the present invention relates to a fetal monitor. A fetal monitor measures and records the fetal beat-to-beat heart rate (FHR) and the uterus activity (toco) simultaneously, which allows an exact determination of the fetal condition. The fetal beat-to-beat heart rate may be obtained from an electrocardiogram signal, e.g., via a spiral electrode screwed into the fetal epidermis, or by the Doppler shift of an ultrasound signal (the moving parts of the fetal heart, i.e., its valves and walls, cause a Doppler shift in the reflected ultrasound wave). The maternal electrocardiogram may be recorded as well. Although the specific embodiment described herein is a fetal monitor (in fact, the present invention was made during the design process of such a fetal monitor ), the invention may also be applied to other kinds of instruments.
The lack of available space for all kinds of monitoring devices presents a serious problem in both hospitals and the private practices of physicians. There are several clinical applications, e.g., the operating room, where multiple physiological parameters of a patient must be monitored. Efforts have already been made to combine several medical monitoring devices in multi-parameter monitors or to incorporate various monitors in a cabinet. In the private practice of a physician, this usually does not help; although only one or very few medical parameters are recorded there, the available space is considerably less than in a hospital. This is particularly true in the case of an antepartum monitor, i.e., a fetal monitor used for screening measurements during gestation. However, even in hospital applications, the solutions of a cabinet or a combined monitor are not always adequate.
A basic goal of the inventor of the present invention is to provide a medical monitor which can be operated in both a horizontal position, as usual, and also in a vertical position. It would thus become possible to use the medical monitor on a desk, a shelf, etc., and also to hang it on a wall or the like and operate it from there. This would not only save considerable space, but would also be useful in placing the monitor close to a patient's bed.
The feature of vertical operation would be particularly suited for monitors which are light or have a relatively flat casing. Furthermore, it would be of particular value for monitors without a bulky CRT, although even monitors with a CRT could be operated in the vertical position.
If operated in a vertical position, the medical monitor could be hung up on a wall in any convenient manner, e.g., using hooks, screws or the like.
When designing a medical monitor, e.g., a fetal monitor, for operation in a vertical position, a problem encountered in a hospital or medical environment in general is that the monitor must be resistant to the spray of water and disinfection fluids as well as spillage of these and other fluids. The operation of the monitor must not be impaired when a fluid is spilled over the monitor. In industrial practice, the required safety of the monitor is therefore usually tested in a "spillage test."
The requirement outlined above cannot be fulfilled if the connector jacks of the medical monitor are, as is usual in the art, placed on the rear panel of the monitor, as the rear panel becomes the upper panel in the vertical position. The same is true for the power inlet. If one of these jacks were placed at the rear panel, i.e., the upper panel in the vertical position, a fluid spilled over the monitor would penetrate into its casing, causing the monitor to malfunction.
It is therefore a major objective of the present invention to provide a medical monitor which may be operated in a horizontal position and also in a vertical position, whereby safe operation is particularly ensured in the vertical position when a fluid is spilled or sprayed over the monitor.